Electric steam boiler



Nov. 5, 1957 c. A. STEEN ELECTRIC STEAM BOILER Filed Nov. 3, 1954 United States Patent 2,812,416 ELECTRIC STEAM BOILER CarlAugust Steen, Getinge, Sweden Application November 3, 1954, Serial No. 466,539

Ciaims. (Cl. 219- The invention relates to an electric steam boiler, comprising electrodes suspended from an adjustable carrier. Such boilers have usually means for regulating the feed water supply so that the water level is maintained as constant as possible. By raising and lowering the electrodes the steam generation may be reduced or increased, and an object of the invention is to provide a simple, effective and automatic device for regulation of the steam generation in dependence of the steam consumption in order to maintain a substantially constant steam pressure.

The invention is more clearly described hereinafter in connection with the accompanying drawing, in which:

Fig. 1 is a vertical sectional view of a boiler accord ing to one form of the invention.

Fig. 2 is a sectional view on line IIII in Fig. 1.

The boiler is made with an upright cylindrical casing 1, a bottom portion 3 with legs 2 and an upper removable portion 4 with a flange 5 secured by bolts to a flange 6 projecting from the casing 1. The electrodes consist of three metal strips bent to sector-formed electrodes 7 and forming together a cylindrical body of a height considerably less than its diameter. As a consequence of this form an insignificant change of the position of the electrodes results in a considerable change of the contact surface of the electrodes and the steam generation.

The water level V is maintained constant by any known, automatic feed water supply device, but this device as well as other conventional armatures are not shown in the drawing.

A plate 8 is formed with three arms provided each with an insulated contact pin 9 carrying one electrode 7 and being connected by a wire 10 to the inlet 11. A tube 12 is welded to the plate 8 and serves as an electrode carrier, and the tube passes through a guide 14 fixed to or pivotedly connected with one or more brace rods 13. Secured to the tube is a set collar 15, which in the lowest position of the electrode carrier rests on the guide 14 as shown in Fig. 1. The tube 12 is hingedly connected with one end of a lever 16, whereas the other end thereof is pivoted in a fixed stud 17, and the lever with the electrodes can thus be swung by means of a vertical draw member or rod 18 pivoted at its lower end in an intermediate point of the lever 16.

The cover 4 of the boiler has an opening with a socket 19, and a bellows 20 is removably fastened with its lower end around the socket and is closed at its upper end by the end wall 21. The rod 18 passing through the opening is secured by welding to the end wall. To the upper side thereof is welded a bearing fork 22 for a loading lever 23 pivoted at one end in a stud 24 on the cover 4 and provided with a slidable weight 25 for regulation of the normal steam pressure.

The bellows can be made of metal, rubber, a synthetic material, such as plastic, or another suitable material. If a non-metallic material is used, the side wall of the bellows may be reinforced in a suitable way, preferably by means of metal rings at some distance one 'ice from another. The side wall may have one or more folds and be made with cylindrical, conical or doubleconical outline, and the end wall is preferably made as a rigid metal plate.

When the boiler operates at the normal pressure, the steam exerts a pressure on the end wall, which is balanced by the load and the weight of the movable electrode system. If the supply of steam should increase, the steam pressure will decrease and cause a lowering of the end wall and the electrodes, until the steam pressure is substantially restored, and if the steam supply should be cut off, the electrodes will be raised and the contact surface reduced to such an extent that the steam generation corresponds only to the heat losses of the boiler. By the transmission ratio between the movements of the end wall and the electrodes as shown in principle in the drawing it is possible to maintain the movement of the bellows within narrow and for practical use suitable limits.

The invention is preferably used in a boiler for a relatively low pressure. As the bellows hermetically closes the opening in the boiler wall no leakage is obtained. The regulation is performed without any substantial friction and is thus very sensitive. If the cover 4 is unfastened and raised somewhat, the wires 10 can be dis connected, and thereafter the cover 4 with the whole electrode system may be removed as a unit.

I claim:

1. An electric steam boiler comprising a casing having a wall, a set of electrodes located in said casing in spaced later-a1 relation and having together the outer form of a cylinder of a height considerably less than its diameter, an electric conductor to each electrode for supplying electric current to pass between the electrodes, a vertically adjustable carrier for said electrodes, said wall having an excentrically located opening, a bellows fastened hermetically at one end to said wall around said opening and having its other end closed by a top plate, a control rod secured to said top plate and connected by a link mechanism with said electrode carrier for raising and lowering the electrodes in dependence of the steam pressure, and a loading device acting on said top plate and comprising a lever with a slidable weight.

2. A steam boiler as claimed in claim 1, wherein said casing has a removable top portion, said electrode carrier, and bellows, and the connection between them being mounted on said removable top portion.

3. An electric steam boiler, comprising a casing, a plurality of electrodes electrically insulated from each other within the casing, each electrode comprising a horizontally extending strip of sheet metal having vertically turned side surfaces and all of said electrodes being located at the same level and at some horizontal distance from one another, said casing having an electric inlet for each of said electrodes, an electric conductor between each of said electrodes and its corresponding inlet in the casing for connection of the electrodes to different cur rent phases so as to pass a current between said electrodes, a vertically adjustable carrier for said electrodes, a bellows fastened hermetically at one end to the casing around an opening in said casing and having its other end hermetically closed by an end plate, and a link mechanism between said end plate and said carrier for raising and lowering the electrodes in dependence of the steam pressure.

4. An electric steam boiler, comprising a casing, a plurality of electrodes, means for electrically insulating said electrodes from each other within said casing, each electrode comprising a horizontally extending strip of sheet metal having vertically turned side surfaces and all of said electrodes being located at the same level and at some horizontal distance from one another, said c-asing having an electric inlet for each of said electrodes, an electric conductor between each of said electrodes and its corresponding inlet in the casing for connection of the electrodes to diiferent current phases so as to pass a current between said electrodes, a vertically adjustable carrier for said electrodes, a support mounted on said casing, a lever pivotally connected at'its one end with said carrier and at its other end with said support, said casing having a control opening, a bellows located outside said casing and fastened hermetically at its lower end to the casing around said control opening, an end hermetically closing the upper end of said bellows, and a control rod secured to said end plate and connected with said lever at a point between the ends thereof. 7

5. A steam boiler as claimed in claim 4, an adjustable loading device connected with said end plate of said bellows.

References Cited in the file of this patent UNITED STATES PATENTS 

